No. Just stay with the Chao for about ~1 hour and it should evolve.
Time only passes in the Gardens while you're
in them.
Added:
alexa999 said:
Give an egg fertily fruit to a chao and it will become an adult. (And a good gardner, the flowers.):happy:
Fertility fruits don't do anything to infant Chaos (well, actually, that isn't entirely true but isn't a lie either).
Giving a fertility fruit to an adult Chao will force it into a 'mating season' and/or make it more amenable to mating with a Chao that's already in season.